Various techniques such as a technique using a reference light and a stereo ranging technique using a plurality of cameras are known as imaging techniques for obtaining a depth-direction distance to a subject, serving as two-dimensional array information. In particular, in recent years, imaging devices capable of obtaining distance information at relatively low costs have been increasingly needed to serve as newly developed consumer input devices.
An example of distance imaging methods that do not use any reference light in order to save system costs is a triangulation method using parallaxes. Stereo cameras and compound-eye cameras are known as devices using such a method. These cameras, however, each use two or more camera elements, which causes such problems as an increase in the size of the systems, and an increase in failure rate caused by an increase in the number of system components.
A known structure of imaging devices capable of obtaining distance information has a microlens array arranged above pixels, so that a few pixels are located below a corresponding microlens. With such a structure, images with parallaxes can be obtained in the units of pixel blocks. The parallaxes make it possible to estimate the distance to a subject, and to perform re-focusing based on such distance information.
If a microlens array is formed of microlenses of the same type having the same focal length, the magnification of a reconstructed image is determined based on the distance to the subject. For this reason, it is not possible to obtain, using such a microlens array, an image formed with another magnification for the same distance to the subject. In order to vary reconstruction magnification, a voice coil motor or actuator should be equipped to the imaging device.